Braided fuel line - Page 2 - PeachParts Mercedes-Benz Forum

vstech · #16 02-13-2009, 09:55 AM

Quote:

Originally Posted by SD Blue

First of all, do you understand what "From my understanding" means?

We are talking about two different things but I noticed this comment agrees with me.

However, if there is "no pressure", describe what the cigar hose does. Also, why is the return nipple of the return so much smaller than the injection line? Or better yet, you tell us why there is even a return line at all?Granted, it's a small back pressure created by restriction.

well, From MY understanding, the cigar hose is large to quiet the return pulses of fuel entering the firewall. also from my understanding, the entire return line setup, dumps fuel into the fuel tank. so any air in the lines, would go to the tank, and be vented to atmo.

SD Blue · #17 02-13-2009, 11:13 AM

Quote:

Originally Posted by vstech

........... the entire return line setup, dumps fuel into the fuel tank. so any air in the lines, would go to the tank, and be vented to atmo.

Well, isn't that what I said in my original post?

I realize that I didn't originally answer his question completely, with regards to how a leaking return line can cause air in the system, but my intention was to help not self-proclamation of being an expert. I leave that to others.....

Diesel911 · #18 02-13-2009, 03:29 PM

Quote:

Originally Posted by SD Blue

First of all, do you understand what "From my understanding" means?

We are talking about two different things but I noticed this comment agrees with me.

However, if there is "no pressure", describe what the cigar hose does. Also, why is the return nipple of the return so much smaller than the injection line? Or better yet, you tell us why there is even a return line at all?Granted, it's a small back pressure created by restriction.

Sometime when your have your Injection Line off take a look at the inside diameter of the Injection Line and compare it to the inside diameter of the Fuel Return Nipples. (The outside diameter of the Injection Line is large as it has to handle the injection pressure.)

The inside diameter of the Fuel Return Nipples is smaller but not much.
Also not as fuel volume is passing throught the Fuel Return Nipples as most of the fuel gets injected into the Engine.

The rest leaks by the Injector Spray Nozzle Pintel and lubricates and cools it by carring heat away from the Spray Nozzle. (For a similar reason most of the Fuel passing through the IP is to cool and lubricate the IP.)

The only fuel injecting system I have seen with out fuel return line is on one of the models of a Catapillar Engine. The Injectors are inside and under the Valve Cover and it may be that they did not want the extra plumbing to route return lines to the outside or did not want the possibility of a return line going bad and leaking Fuel into the Engine Oil.
This is a rather poor pic of the injector.

JCSC2 · #19 02-17-2009, 08:14 AM

Just wanted everyone to know I successfully changed the return line. The lines were a lil bit hard to take off but. I gently cut them on both ends and got them pulled off. Spilled a bit of fuel but it went pretty smoothly. Thank you for everyone's help.

yellowrosefarm · #20 02-17-2009, 08:07 PM

When I changed out the return line on my 240TD, I got the line from the local Mercedes dealer. They were close and had it in stock, which was good because I NEEDED it.